Multifunctional PVC/Polyurea Nanocomposite Foams Empowered by Bicontinuous Phase Structure: Synergistic Reinforcement and Smart Applications

The comprehensive performance of polymer foams strongly depends on the hierarchical structure of the foams, including the molecular chain structure of the matrix material, the aggregation structure (such as phase structure) of the cell wall, the cell structure, and the expansion ratio. In this work, coarse-grained molecular dynamics (CG-MD) simulation was used to predict the formation of phase separation structure within the cellular wall in poly(vinyl chloride)/polyurea (PVC/PUA) nanocomposite foams under different curing temperatures, which provides a guide for preparing the foams with high performance through the “Plasticizing-Foaming-Reinforcing” (PFR) method. It is found that a bicontinuous phase structure within the cellular wall is easily formed at a lower curing temperature. We demonstrate the strong influence of the phase structure of the cellular wall on the comprehensive performance of PVC/PUA nanocomposite foams. PVC/PUA nanocomposite foams with a bicontinuous phase structure within the cellular wall presented better mechanical performance. Also, PVC/PUA foams with a higher PUA content presented better mechanical performance. The presence of bicontinuous phase morphology provided excellent solvent resistance as well as rapid shape recovery capabilities to PVC/PUA nanocomposite foams. Ultimately, a strong synergistic effect between the matrix composition and the phase structure of the cellular wall on the comprehensive performance was revealed.